The flash mob, once a novel and artistic construct used to make urban life that much more quirky and full of possibility, is now the subject of a Howie Mandel show. So it was only a matter of time before flash mobs degenerated into something ugly, violent, and antisocial. Yesterday, a shooting at Venice Beach sent crowds scattering. Why?

The shooting occurred amid a "flash mob" crowd that was organized at least in part over Twitter, Vasquez said.